<script lang="ts" setup name="SealCarousel">
// vue3的写法
// defineProps({
//   slides:{
//     type:Array,
//     required:true
//   }
// })

// vue3+ts写法

import {BannerItem} from '@/types/data'
import { ref, onMounted, onUnmounted} from 'vue';
const props = withDefaults(defineProps<{
  slides:BannerItem[]
  duration?:number
  autoplay?:boolean
}>(),{
  duration:3000,
  autoplay:false
})


// 设置初始下标值
const active = ref(0)

// 点击上一张与下一张
const prev = ()=>{
    active.value--
    if(active.value<0){
      active.value = props.slides.length-1
    }
}

const next = ()=>{
    active.value++
    if(active.value>props.slides.length-1){
      active.value = 0
    }
}

// 自动轮播
let timer = -1
onMounted(()=>{
  start()
})

onUnmounted(()=>{
  stop()
})

// 鼠标 进入/离开 区域时 停止/开启 轮播图
const start = ()=>{
  // ts认为该setInterval是node中的setInterval，不是浏览器的setInterval
  // 解决方案：添加window
  if(!props.autoplay) return 
  timer = window.setInterval(()=>{
    next()
  },props.duration)
}

const stop = ()=>{
  window.clearInterval(timer)
}
</script>

<template>
  <div class="seal-carousel" @mouseenter="stop"  @mouseleave="start">
    <!-- 轮播图片区域 -->
    <ul class="carousel-body">
      <li class="carousel-item" :class="{fade:index===active}" v-for="item,index in slides" :key="item.id">
        <RouterLink to="/">
          <img
            :src="item.imgUrl"
            alt=""
          />
        </RouterLink>
      </li>
    </ul>
    <!-- 上一张 -->
    <a 
      href="javascript:;" 
      class="carousel-btn prev"
      @click="prev"
    >
      <i class="iconfont icon-angle-left"></i>
    </a>
    <!-- 下一张 -->
    <a href="javascript:;" class="carousel-btn next" @click="next"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <!-- 小圆圈 -->
    <div class="carousel-indicator">
      <span 
        :class="{active:index===active}" 
        v-for="item,index in slides.length" 
        :key="item"
        @click="active=index"
      >
      </span>
    </div>
  </div>
</template>

<style scoped lang="less">
.seal-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>